Modular form for cast-in-place concrete decks federally sponsored research

ABSTRACT

A forming system for cast-in-place concrete decks supported by structural beams capable of being used on decks with varying dimensions between the structural beams. The forming modules ( 28, 30 ) interlock with the supporting ledger assemblies ( 10 ) to prevent lateral movement of the form system. The deck material between outside form assemblies ( 26 ) is fabricated to the size required to fill the gap between the outside form assemblies ( 28 ), and is supported by the interior support beams ( 16   b ) or the interior support beams ( 16   b ) and the inside form assembly ( 30 ).

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING OR PROGRAM

Not Applicable

APPLICATION NUMBER

60/558,641, Filing Date 2004 Apr. 1

BACKGROUND

1. Field of Invention

This invention relates to forms for cast-in-place concrete, specifically to such forms that are used for deck slabs supported by structural beams.

2. Prior Art

Cast-in-place concrete deck slabs supported by structural beams are commonly found in the construction of bridges. These bridges carry vehicles, railroads and pedestrians over low areas, roads, railways, water, and other obstructions. These obstructions often prevent the use of heavy equipment to construct the cast-in-place concrete deck.

To construct a bridge, a foundation structure is built at each end of the bridge. Additional foundation structures may be installed between the ends of the bridge. Lines of structural beams are placed longitudinally on top of these foundations the length of the bridge. The structural beams are typically made of steel or steel-reinforced concrete. The transverse spacing between the structural beams is typically between 4 and 8 feet. These lines of structural beams will support the cast-in-place concrete deck.

Forms for the cast-in-place concrete deck are suspended from the structural beams. FIG. 1 and FIG. 2 show prior art that support these forms. A bridge deck hanger assembly 14 is placed on top of a structural support beam 12. The hangers 14 are available in a variety of styles, Dayton/Richmond Concrete Accessories Bridge Deck Forming Handbook 5/99A, Rev. 10/00, Dayton Superior Corporation, pages 2.1 to 2.16. The hangers 14 allow threaded-rod to hang vertically on each side of the beam 12. The hangers 14 are spaced equally along each line of beams 12. Each hanger 14 is parallel to the hanger 14 on the adjacent beam 14. A ledger assembly 10 is suspended from each side of the hanger 14. The ledgers 10 span in a perpendicular direction between adjacent lines of the beams 12.

Joists are installed across the ledgers 10, parallel to the beams 12. Plywood is placed over the joists, and blocking is installed between the hangers 14, Dayton/Richmond Concrete Accessories Bridge Deck Forming Handbook 5/99A, Rev. 10/00, Dayton Superior Corporation, pages 2.7 and 2.19. The height of the plywood above the top of beam 12 is adjusted to account for the deflection of beam 12 caused by the weight of the concrete. This adjustment is made by raising or lowering the nut on hanger 14 supporting the ledger 10.

The difficulties with this system are numerous. Cast-in-place concrete deck forms are installed on top of the structural support beams, but must be removed from beneath the finished cast-in-place concrete deck. The same obstructions that require the construction of the bridge often impede the access of heavy equipment to remove the deck forms. The structural support beams often contain cross bracing that preclude the use of large form panels.

The spacing and size of the structural support beams vary, depending on the length of span and load supported. A deck forming system has to be able to adapt to the variable spacing between the structural support beams.

A square section of lumber is often used for joists. The reason is that the square section does not roll over before the plywood is installed. The disadvantage to this section is that it is structurally inefficient. Another disadvantage to this section is its weight. A 16 foot long joist that is typically used weighs approximately 60 pounds. A more rectangular section would allow the same load to be carried with smaller, lighter, and less expensive lumber. Another example of inefficiency is the way in which plywood is used on top of the joists. The distance between the edges of the structural support beams is usually more than 4 feet but less than 8 feet. Plywood is typically installed with the 8 foot edge parallel to the joists. The 34 inch thick plywood sheet typically used weighs over 70 pounds. A thinner, lighter, and less expensive section of plywood can be utilized if the plywood is installed so that 8 foot edge is perpendicular to the joists. In addition to being more expensive, the less efficient and heavier sections increase the risk of injury to the workers due to over exertion.

The use of stock sizes of dimensional lumber and plywood for joists, blocking and plywood necessitate many pieces that must be manually cut to size. These pieces must then be installed and removed, making the operation extremely labor intensive.

Numerous attempts have been made to improve this process. The adjustable concrete form in U.S. Pat. No. 975,242 issued to Higgens et al, 1910 Nov. 8 and floor construction in U.S. Pat. No. 1,415,554 issued to Hatch, 1922 May 9 have no adjustment for the deflection of the structural support beams. The concrete form in U.S. Pat. No. 2,344,841 issued to Weber, 1944 Mar. 21 has no adjustment for variations between the structural support beams. The concrete slab form in U.S. Pat. No. 3,170,217 issued to Williams, 1965 Feb. 23 requires a supporting angle to be installed on the structural support beam. The adjustable floor and roof form in U.S. Pat. No. 1,652,056 issued to Selway, 1927 Dec. 6 cannot accommodate cross bracing between the structural support beams.

The concrete form support bracket and assembly in U.S. Pat. No. 6,273,393 B1 issued to McCoy, 2001 Aug. 14 and interior and fascia forms for concrete in U.S. Pat. No. 3,806,074 issued to Ward, 1974 Apr. 23 eliminate the use of joists, which greatly increases the number of hangers that must be installed and adjusted. Also, as there is no adjustable feature, each component must be cut to size. The form decking apparatus for bridges in U.S. Pat. No. 5,483,716 issued to Burnaman, 1996 Jan. 16 requires that the form channels be connected with an interior connection. To remove this forming system, the components must be pulled apart parallel to the underside of the concrete deck. Forms are easier removed by pulling them down from the concrete deck. Also, the use of T-plates for filler panels creates variations in the thickness of the deck.

The bridge deck construction forms in U.S. Pat. No. 6,401,286 B1 issued to Brenn, 2002 Jun. 11 utilize sloped filler panels from the form to the structural support beams. These sloped filler panels require additional concrete be used in constructing the deck. The additional concrete, in addition to adding weight that must be supported, requires additional steel reinforcing to maintain integrity with the deck. The use of horizontal connecting pins on multiple sides of the form unit make removal extremely difficult.

OBJECTS AND ADVANTAGES

The objects and advantages of the present invention are:

-   -   (a) to provide a re-usable form for cast-in-place concrete decks         supported by structural beams;     -   (b) to provide a form that can be used on cast-in-place concrete         decks with different dimensions between the supporting beams;     -   (c) to reduce the labor required to install and remove forms for         cast-in-place concrete decks by reducing the number of         components required;     -   (d) to reduce the labor and reduce the potential for injury when         installing and removing forms for cast-in-place concrete decks         by reducing the weight of the components;     -   (e) to reduce the quantity of material used in forming         cast-in-place concrete decks by use of more efficient materials;     -   (f) to reduce the amount of natural resources expended directly         in the construction of cast-in-place concrete decks by use of         more efficient materials;     -   (g) to reduce the amount of natural resources expended         indirectly in the construction of cast-in-place concrete decks         by decreasing the time required to construct a cast-in-place         concrete deck, therefore reducing the delays to commuters and         wasted fuel associated with those delays.

Further objects and advantages of the modular form for cast-in-place concrete decks will become apparent from a consideration of the drawings and ensuing description.

SUMMARY

The modular form for cast-in-placed concrete decks is a re-usable form. It is adjustable to fit varying structural support beam spacing. The modular form for cast-in-place concrete decks is faster to install because the number and weight of the components has been reduced.

DRAWINGS

Drawing Figures

FIG. 1—is a perspective showing the supporting structural beams, beams hangers used to support the formwork, and the ledger assembly that is hung from the beam hangers.

FIG. 2—is a perspective showing the plate washer and nut being attached to the beam hanger to suspend the ledger assembly.

FIG. 3—is a plan view of the invention.

FIG. 4—is a cross section of the invention.

FIG. 5—is a perspective of the invention being placed on top of the ledger assembly.

FIG. 6—is a plan view showing multiple modular forms installed between structural support beams with filler panels.

FIG. 7—is a cross section showing the outside and inside modular forms with filler panels on top of the ledger assembly.

FIG. 8—is a cross section showing how adjacent modular forms are interlocked into the void of the ledger assembly.

FIG. 9—is a perspective of the modular forms installed with the concrete deck on top

REFERENCE NUMERALS IN DRAWINGS

-   10—ledger assembly -   12—structural support beams -   14—bridge deck hanger assembly -   16—modular form, support beam -   18—modular form, end plate -   20—modular form, deck material -   22—modular form, recess for bridge deck hanger assembly -   24—modular form, exposed beam for support of adjacent deck material -   26—deck material between outside form assemblies -   28—outside modular form assembly -   30—inside modular form assembly -   32—concrete -   34—reinforcing steel -   36—void in ledger assembly

DETAILED DESCRIPTION

Description—FIGS. 1-9, Preferred Embodiment

FIG. 1 shows a structural support beam 12. A bridge deck hanger assembly 14 is placed over the structural support beam 12. A ledger assembly 10 is then suspended from the bridge deck hanger assemblies 14.

FIG. 2 shows how the nut and washer attach to complete the deck hanger assembly 14.

FIG. 3 is a plan view of an outside form assembly 28. FIG. 4 is a cross section of an outside form assembly 28. The outside form assembly 28 is comprised of:

-   -   (a) A pair of parallel support beams 16 that carry the load to         the ledger assemblies 10.     -   (b) A pair of end plates 18 that attach to the end of the         support beams 16. The end plates 18 extend below the support         beams 16. The thickness of the end plates 18 is nominally one         half the width of a void in the ledger assembly 36 (see FIG. 2         and FIG. 8). The end plates 18 provide interlock with the ledger         assemblies 10 and lateral support for the support beams 16.     -   (c) A deck material 20 is attached to and spans the support         beams 16. The span of the deck material 20 is from the outside         edge of the exterior support beam 16 a to one-half the width of         the interior support beam 16 b. One-half of the interior deck         beam 16 a exposed for support of adjacent deck material 24.     -   (d) A recess for deck hanger assemblies 22 is made in each end         of exterior support beam 16 a. The dimension of the recesses is         nominally one-half the area of the deck hanger assembly 14 (see         FIG. 1 and FIG. 5).

An inside form assembly 30 is identical to an outside form assembly 28, with the following exceptions:

-   -   (a) no deck material 20 is attached to the support beams 16;     -   (b) the recess for deck hanger assemblies 22 is omitted.

The inside form assemblies 30 and the outside form assemblies 28 are the same length.

FIG. 5 shows the outside form assembly 28 being placed on the ledger assembly 10. The end plate 18 drops into the void in the ledger assembly 36. The recess for the bridge deck hanger assembly 22 fits around one-half of the deck hanger assembly 14.

FIG. 6 shows the ledger assemblies 10 installed on support beams 12. Bridge deck hanger assemblies 14 are not shown for clarity. The ledger assemblies 10 are spaced at the same dimension as the length of the outside form assemblies 28 and inside form assemblies 30. Support beams 16 for outside form assemblies are not shown for clarity. A deck material 26 between outside form assemblies 28 spans from the exposed half 24 of interior support beam 16 b of one outside form assembly 28, across the support beams 16 of the inside form assembly 30 to the exposed half 24 of the interior support beam 16 b of the parallel outside form assembly 28.

FIG. 7 shows the positions of the two outside form assemblies 28 and one inside form assembly 30. The deck material 26 between outside form assemblies 28 is shown as described above. The end plates 18 are shown extending into the void 36 of the ledger assembly 10.

FIG. 8 shows how the two end plates 18 of the outside form assemblies 28 and the inside form assemblies 30, when placed end to end as shown on FIG. 7, interlock into the void 36 in the ledger assembly 10. This interlock prevents the form assemblies from moving laterally.

FIG. 9 shows a completed modular deck form for cast-in-place concrete decks. A deck of concrete 32 reinforced with a reinforcing steel 34 is shown installed on top. The width of the deck material 26 between the outside form assemblies 28 can be changed to accommodate a variety of spacing of structural support beams 12.

In the preferred embodiment, the ledger assemblies 10 and the support beams 16 are fabricated with dimensional lumber. The end plates 18 and the deck material 20 & 26 are fabricated of plywood. The actual measurements and sizes are determined by the spans desired, the width of support beams 12 and the thickness of the cast-in-place concrete deck. To build a cast-in-place concrete deck 8 inches thick, the support beams 16 will be 6 feet long and fabricated of nominal 2 inch×6 inch lumber. The distance between the support beams 16 will be 16 inches. The deck material 20 will be 12 inch plywood. The deck material between outside form assemblies 26 will be 12 inch plywood. The end plates 18 will be 3/8 inch plywood, and the void in the ledger assembly 36 will be ¾ inch.

The weight of the outside form assembly 28 will be approximately 42 pounds. The weight of the inside form assembly 30 will be approximately 28 pounds. The weight of the deck material between outside form assemblies 26 will be approximately 24 pounds.

Alternative Embodiments

Variations of the modular form for cast-in-place concrete decks are possible. Some would include:

-   -   (a) Using more than two support beams 16 to span across the         ledger assemblies 10.     -   (b) Using an alternative shape or material, such as a steel         angle, to provide lateral stability to the support beams 16 and         interlock with the ledger assemblies 10.     -   (c) Using the deck material 20 as a stressed skin member to         increase the load carrying capability of the outside form         assembly 28.     -   (d) Attaching a stressed skin to the bottom of the support beams         16 to increase the load carrying capacity of the outside form         assembly 28 or inside form assembly 30.     -   (e) Using an alternative material, such as aluminum, steel or         engineered lumber for support beams 16 and ledger assemblies 10.     -   (f) Using an alternative material such as steel, aluminum or         composites for deck material 20 & 26.     -   (g) Increase the length of support beams 16 or decrease the         spacing of ledger assemblies 10 to allow the support beams to be         supported by additional ledger assemblies 10.         Advantages

From the description above, a number of advantages of the modular form for cast-in-place concrete decks become evident:

-   -   (a) the modular form reduces the number of components required;     -   (b) the modular form is re-usable;     -   (c) the modular form components weigh less than standard forming         components;     -   (d) the modular form is adaptable to various dimensions;     -   (e) the modular form reduces the labor required to form         cast-in-place concrete decks;     -   (f) the modular form reduces the material required to form         cast-in-place concrete decks;     -   (g) the modular form reduces the potential for injury to         workers;     -   (h) the modular form saves natural resources         Operation FIGS. 1-9     -   1. Bridge deck hanger assemblies 14 are placed on structural         support beams 12 (FIGS. 1 and 2) spaced at the length of outside         deck assemblies 28 and inside deck assemblies 30 (FIG. 6).     -   2. Ledger assemblies 10 are suspended from bridge deck hanger         assemblies 14 (FIGS. 1, 2, 5, and 7).     -   3. Outside form assemblies 28 are placed against structural         support beams 12 (FIG. 5). The outside form assemblies 28 are         place end to end (FIG. 6), with the end plates 18 interlocking         with the ledger assemblies 10 via the void in the ledger         assemblies 36 (FIG. 8). When the outside form assemblies 28 are         placed end to end, the pair of recesses for bridge deck hanger         assemblies 22 create a void that allows the bridge deck hanger         assembly 14 to pass through the form assembly and adjust the         height of the ledger assembly 10 supporting the form assemblies         28 & 30 (FIGS. 5 and 7).     -   4. Inside form assemblies 30 are centered on the ledger         assemblies 10 between the outside form assemblies 28 (FIGS. 6,         7, and 9). Additional inside form assemblies 30 may be used         between outside form assemblies 28 if the spacing between         structural support beams 12 requires. Inside form assemblies 30         may be omitted if the spacing between support beams 12 allows.         The outside form assemblies 28 and inside form assemblies 30 are         parallel to each other and perpendicular to the ledger         assemblies 10 (FIG. 6).     -   5. Deck material 26 is placed between the opposing exposed beam         24 of the parallel outside form assemblies 28 and over the         inside form assembly 30 (FIGS. 6, 7, and 9).     -   6. Reinforcing steel 34 is placed on the deck material 20 and 26         (FIG. 9).     -   7. Concrete 32 is placed on the deck material 20 and 26 (FIG. 9)         and allowed to cure.     -   8. The modular form system is removed.

CONCLUSION, RAMIFICATION, AND SCOPE

Accordingly, the reader will see that the modular form for cast-in-place concrete decks can easily be used to install deck forms, can be used on decks with varying spacing of structural support beams, can be re-used multiple times, can reduce the number of components required for form cast-in-place concrete decks, and can reduce the weight of the components used to form cast-in-place concrete decks. The modular form for cast-in-place concrete decks has additional advantages as it reduces the labor required, it reduces the exposure to injury from over exertion, and it reduces the natural resources consumed while installing and removing deck forms.

While this description contains many details, these details should not be construed as to limit the scope of the modular form for cast-in-place concrete decks. For example, the modular form could be adapted for use on horizontal concrete such as walls. The scope of the invention should be determined by the appended claims and their legal equivalents, rather than the examples given. 

1. A form for cast-in-place concrete comprising: (a) a plurality of parallel beam members (b) a rectangular forming surface superimposed on said beam members (c) means for attaching said forming surface to said beam members at a predetermined distance (d) said forming surface attached to said beam members so the top surface of one of said beam members is not completely covered by said forming surface (e) a supporting beam assembly installed transversely to said beam members (f) said supporting beam assembly containing a void of predetermined dimension (g) means for suspending said supporting beam assembly from structural support beams (h) said beam member contains a void to allow passage of said means for supporting said supporting beam assembly (i) a rectangular member attached to the end of said parallel beam members and interlocking with said supporting beam assembly (j) a rectangular filler forming surface (k) said rectangular filler forming surface is supported by the exposed portion of the top surface of said beam members
 2. The form of claim 1 with an additional support structure comprising: (a) a plurality of parallel beam members (b) means for attaching said forming surface to said beam members at a predetermined distance (c) a rectangular member attached to the end of said parallel beam members and interlocking with said supporting beam assembly of claim 1 (d) said rectangular filler forming surface of claim 1 is supported by the exposed portion of the top surface of said beam member of claim 1 and parallel beam members of additional support structure 